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KOSS ESP.9 Electrostatic Headphones From EBAY

Discussion in 'Headphones (full-size)' started by neophyte, Aug 27, 2003.
  1. Neophyte
  2. mkmelt
    The Koss ESP-9 was a very nice sounding electrostatic headphone. Unfortunately, Koss is no longer repairing these as they are unable to get the needed parts.

    There is supposed to be someone in Germany who rebuilds these phones. If you purchase a pair with an option to return them if they do not work to your satisfaction within two weeks of purchase, then maybe. Otherwise, beware you may be purchasing a headache.
     
  3. Neophyte
    I did more research and found a huge cult following of them. Most say that they blow away stax. Here is an example of the reviews I've read.

    "The Grado's are OK 'phones but I would have thought anyone who is into personal listening must have gone to the source for their equipment. I'm no Crusader so, take this advice or leave it. The nearest KOSS get to the best Grados are the HV/1As. By 'nearest' I mean the KOSS product is infinitely better. The best cans ever made for classical/live/jazz/critical listening are the KOSS ESP/9 and ESP/10 Auditors; for £1,000 they should be and ARE. The Stax electros are nowhere near them. You'll hear stuff the mixdown Engineer didn't wearing the 10's."

    That being said I ended up getting a "working" set (crossing my fingers) but @ $43 US I figured it's worth a shot.
     
  4. JMedeiros Contributor
    Congrats! It sure sounds like 43 bucks worth of ear fun to me [​IMG]
     
  5. Calanctus
    Hey Neophyte,

    Please be sure to post your impressions. I've got a different (probably not as good [​IMG] ) pair of Koss electrostats (ESP 950) but I'm still interested to hear about these.
     
  6. Neophyte
    Hi Calanctus,

    Have you created a review of yours? I just looked up the 905 and they look like a new release? The ones I got are from the 80's The ESP 10 I think also were an 80's product were the top of the line. Here is a link to a pix of the ESP 10. They look quite a bit more impressive than the 9s that I bought.

    http://www.audiocircuit.com/9111-esh...PIC-ESP-10.htm
     
  7. edstrelow Contributor
    I have had a set for over two decades. They have their good points, one being that they are entirely closed circumaural electrostatics, and that is a rare beast indeed. They have good bass and smooth midrange and very nice with most materials and especially pop/rock.

    I don't rate them above even the old Stax Lambdas, which I also have, but the sound can vary with the manner of hook-up. They come with an old-fashioned transformer which is plugged into the power amp. More modern electrostatic units use a separate headphone amp. The transformer means one or more extra processing stages but may give you better dynamics, than most headphone amps, depending on your power amp. So I don't discount the possibility that with the right set-up and some mods, you could get some super sound.

    I note that a reviewer on HEADWIZE reported that the foam backing in the cups shorts out with age, thereby screwing up the set. He recommended taking it out and cleaning the circuit board in place in each earcup and installing new foam.

    Also the old, liquid-filled earpads tend to deteriorate, but can be replaced with more recent foam-filed pads of the same size.
    I have been trying, unsuccesfully and without much real effort to get them to rum off an old Stax, low bias amp.
     
  8. fewtch Contributor
    I wouldn't feel good about buying any kind of older equipment (pre-90's) using transducers, unless I were planning to rebuild or refurbish them. That includes headphones, speakers, mics and NOS phono cartridges. There's just too much stuff to deteriorate and potentially screw up the sound.
     
  9. Calanctus
    Quote:

    Originally posted by Neophyte
    Hi Calanctus,

    Have you created a review of yours? I just looked up the 905 and they look like a new release? [/url]



    I did post something on headwize but I can't locate that post anymore (comparison of ESP 950 and DT 770, heh). I don't think the 950s are that new; I've had mine for a few years now. They are impressive phones in that you can turn them as loud as you want and they maintain a very clear sound without any distortion.
     
  10. jstachowski
    Hi---
     
      I still have a set in my closet.  I bought my set used in the '70s and found that you need a fair amount of power to drive them. The earcushions need to be replaced periodically.  Even then they tend to exert a fair amount of pressure on your ears.  But the sound is worthwhile.  I still remember being amused when I first got them that they came with a response graph.
     
       One things to watch out for is that they tie the grounds from the two channels together.  Some amps show their appreciation by blowing up.
     
  11. denden
    I have a pair of ESP 9s that I inherited off my father. I remember them sounding quite good. He had them hooked up to a dedicated Musical Fidelity power amp. They have not been used since he died about 9 years ago. I will have to make do with using my mataxas Iraklis power amp that shares duties with my loudspeakers. I am pretty keen to try them out but I am a bit scared of blowing the amp and finding replacements for the flat ear pads.
     
  12. jstachowski
    Hi---
     
      One thing to watch for is that they tie the grounds of the two channels together.  I used to use a Marantz 2270 to drive mine with, and it worked well. (So about 93 W)  I spoke to a Koss rep at RMAF last year, and he said the only replacement parts they have is ear cushions.  I still have mine, but they've sat on the shelf for about 10 years, since I have the ESP 950s.  
     
       I'll have to replace the foam in mine, but I still remember them fondly.  My major complaint with them with was the pressure, but I used to wear them for many hours a day, (up to 6 hrs), and they far out shown the speakers I owned in those day.
     
  13. KlarkKentThe3rd
    How are those compared to http://www.koss.com/en/products/headphones/full_size_headphones/ESP950__ESP950_Electrostatic_Headphone ?
     
  14. jstachowski
    Hi---
     
      The ESP 9's were isolating phones, where as the ESP 950s are non isolating.  The 950s are much easier to wear for a prolonged period of time.  The ESP 950s are much easier to drive, you don't need a speaker level output to drive it, just a headphone output will do.  Of course, the 950 will let you hear in painful detail exactly what is wrong with your headphone output.  It seems like ESP 9 were flatter.  At least when I got my 9s they gave me a frequency response chart that was flat.  
     
  15. aptr91
    Have you the graphs?
     

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